Electrical cord connector with improved screwless terminals



March 14, 1967 c. T. VON HOLTZ 3,309,647

ELECTRICAL CORD CONNECTOR WITH IMPROVED SCREWLESS TERMINALS Filed July '7, 1964 wax &

United States Patent 3,309,647 ELECTRICAL CORD CONNECTOR WITH IM- PROVED SCREWLESS TERMINALS Charles T. Von Hoitz, Bridgeport, Conn., assignor to Harvey Hubbell, Incorporated, Bridgeport, C0nn., a corporation of Connecticut Filed July 7, 1964, Ser. No. 380,824 6 Claims. (Cl. 339-474) This invention relates to electrical cord connectors and, particularly, to an improved electrical cord connector having improved means for connecting the usual lead wires of the electrical cord to the contacts of the connector which eliminate the need for the usual binding post screws or sim lar attaching means.

In Webster Patent No. 2,920,304, entitled, Locking Elecrical Cap and Connector issued Ian. 5, 1960, and assigned to the assignee of the instant application, there is disclosed and claimed an improved electrical cord connector wherein screwless terminals are employed. The subject matter of the Webster patent has gone into wide scale successful commercial usage. It is an object of this invention to improve electrical connectors of the type disclosed in the Webster patent to the end of providing an improved, simple, quick, absolutely safe and secure screwless terminal means for connecting the lead wires of the electrical cord to the contacts of the connector.

The object of the invention is achieved in one form by providing in an electrical connector of the Webster patent type, an individual cup-shaped terminal member made of a very soft thin-walled good electrical conductive material on the extremity of each bared lead wire of the electrical cord, securely mounted thereon as by crimping, to retain all portions of the bared electrical lead wire, particularly if it is of the starnded wire type, within the terminal member, and to mount the terminal members to effect good electrical and mechanical connection with the electrical contacts of the electrical connector when the latter is fully assembled.

Other objects and further details of that which I believe to be novel and my invention will be clear from the following description and claims taken with the accompanying drawing, wherein:

FIG. 1 shows an exploded perspective view of a portion of a single electrical lead wire having a bared end of the stranded wire type and a cup-shaped terminal member for enclosure of and securement to the bared lead wire end before assembly;

FIG. 2 is a side elevation view, enlarged relative to FIG. 1, showing a fully assembled terminal member-electrcal lead wire with portions broken away for clarity;

FIG. 3 is a front elevational view of the FIG. 2 assembly with portions broken away and shown in section for clarity;

FIG. 4 is an elevational view of-an electrical cord conector embodying the invention looking toward one inner surface of one of the connectors housing members; and

FIG. 5 is a side elevational view of the FIG. 4 electrical connector with portions broken away and shown in section for clarity on line 55 of FIG. 4.

The general type of electrical cord connector to which the instant invention relates is fully disclosed in the referred-to Webster patent. It may comprise either a connector cap or a connector body; in the application drawings herein, in FIGURES 4 and 5, a connector cap embodiment of the invention is illustrated as exemplary.

With reference to FIGURE 5, the general construction of the electrical connector cap will be quickly understood. It comprises a pair of cooperating housing members and 12 formed of a suitable electrical insulation material, such as a moldable electrical insulating plastic material, which are detacha bly secured together by a plurality of longitudinally extending screws 14, one of which is shown in dotted lines in FIGURE 5. The housing members 19 and 12 are designed and constructed to mate in a predetermined manner and are keyed so as to be properly oriented in assembly. The mated housing members are covered by a metallic shell 16, in a fiat end wall 18 of which are formed a plurality of the threaded collars 20 for receiving threaded end portions of the screws 14 to assemble the shell armored connector housing. The shell 16 also includes conventional means for supporting a pair of cord clamps 22 of a suitable type for rigidly clamping an electrical cord 23 to the connector to function in a well-known manner as strain relief therefor.

The electrical cord 23 comprises an encased plurality of suitably insulated individual conductor wires 24- which are separated and have their ends bared and disposed where electrical connection to the contacts 26 is made on the interior of the connector housing.

The housing member 1% includes an enlarged central longitudinally extending cord opening 28 which communicates with a plurality of pocket-like recesses 30 for-med in housing member 10 which are angularly spaced and extend radially in and through the inner surface 32 of the hous ing member If The bottom of each recess 30 is formed by a wall having an uneven surface 34, in the nature of a saw tooth in cross section. About the radially outer portion of each recess 30 there is formed a raised U-shaped rib 36 projecting beyond surface 32.

The housing member 12 includes an inner surface 38 and supports a plurality of electrical contacts 26, which in the illustrated electrical connector cap embodiment, comprise electrical contact blades. Blades 25 are illustrated as being of the interlocking type having lateral locking lugs 40 formed at their free ends. Contact blades 26' are securely mounted in the housing member 12 and each has a flat contact plate portion 42 rigidly secured at its inner end disposed adjacent the inner surface 38. Each contact plate portion 42 is thin-walled and bent so as to be capable of being distorted slightly when the electrical connector is fully assembled to generate some contact pressure against the lead wire terminals of the electrical cord, as will become apparent. Adjacent each contact plate portion 42 there is formed a U-shaped recessed portion 44 which complements the U-shaped projecting rib 36 of the housing member It). When the housing members 19 and 12 are fully assembled, as can be seen in FIGURE 5, their inner surfaces 32 and 38 are contiguous and a portion of the Ushaped rib 36 is disposed in the recessed portion 44. This arrangement produces individual substantially enclosed compartments in the connector housing for each of the lead wire terminals.

Each of the electrical lead wires 24 includes a bared end 46, which is illustrated as being of the stranded wire type. With particular reference to FIGURES l to 3, the construction of the electrical lead wires will be clearly apparent. In these figures, one lead wire is illustrated, as exemplary, and it comprises the lead wire 24 having the bared stranded lead wire end 46 about which is securely mounted a deformed terminal member 48, which is illustrated in its original tin-deformed cup-shaped condition in FIGURE 1, and as deformed and fully mounted on the bared lead wire end 46 in FIGURES 2 and 3. Originally the cup-shaped terminal member 48 is cylindrical, has somewhat of a flared open end St to facilitate its mounting on a bared stranded lead wire end, and includes a closed round end 52. Cup-shaped members 43 are preferably forrned of thin-walled very soft copper material and may be conveniently mass produced, as by being cut from a thin-walled copper tube and having one end closed and the other flared, or by being drawn on an eyelet machine. When fully mounted, cup-shaped member 48 has been flattened, as by being crimped in a pliers-like tool, so as to be securely mounted on the bared end 46 and to have a pair of generally parallel flattened sides 54, which are preferably roughened as indicated by reference character 56. The roughening may be conveniently effected if a tool having corrugated or serrated jaws or the like is employed. in practice it has been found that cup-shaped terminal members having a side wall thickness of .005 inch have been very successful and capable of satisfying all heat and pull out requirements for connector terminals.

With a terminal member 48 securely mounted on each of the bared lead wire ends 46 and the electrical cord disposed to extend through the opening 28 in housing member 10, to effect electrical connection, the bared lead wire ends 46 are bent to extend in different radial directions and a terminal member 48 is disposed in each recess 30. The housing member 12 having contacts 26 secured thereto is then juxtaposed and properly oriented relative to the housing member so their respective inner surfaces 38 and 32 are adjacent. The securing screws 14 are then actuated to draw the housing members 10 and 12 together to thereby clamp the terminal members 48 securely between the uneven bottom walls 34 of the recesses and the contact plate portions 42 of the contacts 26.

The foregoing screwless terminal arrangement is readily and quickly effected and produces an effective mechanical and electrical connection between the bared lead wire ends 46 and the contact plate portions 42. The terminal members 48 are compressed in individual compartments between the recess bottom walls 34 and the contact plate portions 42, the latter being slightly deformed in assembly of the connector housing and, thereafter, exerting good contact pressure as a result of a tendency to strain relieve themselves. The roughened side walls 54 of the terminal members 48 effect good contact with the uneven bottom walls 34 of the recesses 30 and the contact plate portions 42 of the contacts 26. More importantly, as a result of intentionally making the terminal members 43 of very soft copper, when assembled they conform to the shape of their mating components (recess bottom walls 34 and contact plate portions 42) and are effectively connected thereto. The arrangement is such that electrical wiring of the connector is effected in a quick and easy manner and the resultant connection is safe and secure. It should be particularly noted that by utilizing deformed cup-shaped terminal members 48 on the bared stranded Wire lead ends, it is possible to contain all individual strands within the terminal members and to thereby eliminate the possibility of their being individually severed or damaged, or inadvertently coming into contact with another electrical conducting portion of the connector to effect an undesirable short. Electrical connectors including the improved screwless terminals contemplated by this invention have gone into widescale commercial use and been completely satisfactory in practice, having passed all necessary heating and pull-out tests thereby insuring adequate electrical and mechanical connections. As will be evident from the foregoing description, certain aspects of my invention are not limited to the particular details of construction of the example illustrated, and I contemplate that various and other modifications and applications will occur to those skilled in the art. It is, therefore, my intention that the appended claims shall cover such modifications and applications as do not depart from the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electrical connector comprising: a pair of housing members of electrical insulating material arranged to be connected together to form a connector housing; one of said members carrying a plurality of electrical contacts; the other of said members carrying a plurality of wire electrical conductors, each having a bared lead wire end to be electrically connected to a portion of a contact; said other member having an inner surface provided with a plurality of recesses facing an adjacent inner surface of said one member and individually aligned with said contacts; a thin-walled deformed cup-shaped terminal member made of very soft electrically conductive material secured on each lead wire end; a separate terminal member disposed in a separate recess in engagement with a portion of a separate contact; and means fordetachably securing said housing members together to clamp said terminal members between their associated contact portion and the bottom of their associated recess to effect electrical connections between associated contacts and conductors.

2. The electrical connector defined in claim 1 wherein said terminal member is a deformed originally cup-shaped thin-walled copper member.

3. The electrical connector defined in claim 1 wherein said terminal member is originally cup-shaped and crimped on said lead wire end.

4. The electrical connector defined in claim 3 wherein said terminal member has roughened flattened sides.

5. The electrical connector defined in claim 1 wherein said bottom of said recess is formed by a roughened wall.

6. The electrical connector defined in claim 1 wherein said electrical conductor comprises a stranded wire.

References Cited by the Examiner UNITED STATES PATENTS 2,320,155 5/1943 Papp 339223 X 2,920,304 1/1960 Webster 339-103 X 2,970,288 1/1961 Hubbell et al 339103 X 3,041,577 6/1962 Elliott 339223 X 3,064,072 11/1962 Gralf et al 339-223 X FOREIGN PATENTS 206,521 8/1939 Switzerland.

EDWARD C. ALLEN, Primary Examiner.

W. DONALD MILLER, Examiner, 

1. AN ELECTRICAL CONNECTOR COMPRISING: A PAIR OF HOUSING MEMBERS OF ELECTRICAL INSULATING MATERIAL ARRANGED TO BE CONNECTED TOGETHER TO FORM A CONNECTOR HOUSING; ONE OF SAID MEMBERS CARRYING A PLURALITY OF ELECTRICAL CONTACTS; THE OTHER OF SAID MEMBERS CARRYING A PLURALITY OF WIRE ELECTRICAL CONDUCTORS, EACH HAVING A BARED LEAD WIRE END TO BE ELECTRICALLY CONNECTED TO A PORTION OF A CONTACT; SAID OTHER MEMBER HAVING AN INNER SURFACE PROVIDED WITH A PLURALITY OF RECESSES FACING AN ADJACENT INNER SURFACE OF SAID ONE MEMBER AND INDIVIDUALLY ALIGNED WITH SAID CONTACTS; A THIN-WALLED DEFORMED CUP-SHAPED TERMINAL MEMBER MADE OF VERY SOFT ELECTRICALLY CONDUCTIVE MATERIAL SECURED ON EACH LEAD WIRE END; A SEPARATE TERMINAL MEMBER DISPOSED IN A SEPARATE RECESS IN ENGAGEMENT WITH A PORTION OF A SEPARATE CONTACT; AND MEANS FOR DETACHABLY SECURING SAID HOUSING MEMBERS TOGETHER TO CLAMP SAID TERMINAL MEMBERS BETWEEN THEIR ASSOCIATED CONTACT PORTION AND THE BOTTOM OF THEIR ASSOCIATED RECESS TO EFFECT ELECTRICAL CONNECTIONS BETWEEN ASSOCIATED CONTACTS AND CONDUCTORS. 